1. Technical Field
The present invention relates to a printing apparatus in which continuous paper is printed at least twice with a time difference on one or both of its front and back faces by ink jet printer equipment and is dried as it is passed through a dryer section at each time of printing.
2. Description of the Prior Art
A printing apparatus in which continuous paper is printed twice with a time difference on both of its front and back sides by ink jet printer equipment and is dried as it is passed through a dryer at each time of printing has already been applied for in a patent application filed by the present applicant (see JP 2004-224002 A).
There is also a printing apparatus which is equipped with a heater body for heating continuous paper and in which a moisture condensation or absorbing member is provided in the vicinity of an ink discharge nozzle in a print head to prevent a printing trouble from occurring from condensation on the ink discharge nozzle surface (see JP H01-157860 A).
In a printing apparatus as described in JP 2004-224002 A, when printed continuous paper heated through the dryer for drying the print is again passed along the lower surface of the print head in the ink jet printer equipment, water drops may be created by the condensation on an ink discharge nozzle surface in the print head caused by a temperature difference between the continuous paper and the print head which is lower in temperature than the former with the result that a printing trouble may take place.
On the other hand, in a printing apparatus as described in JP H01-157860 A, while water vapor produced at a place of the paper surface opposed to the print head can be removed by the moisture condensing or absorbing member provided in the vicinity of the print head, there are differences between discontinuous sheets of paper and continuous paper in paper to be printed and also large differences in transport and printing speeds of paper. Thus, with a printing apparatus using continuous paper that is high in both transport and printing speeds, it is difficult to have the rate of condensation and the rate of moisture absorption reaction follow the travel of continuous paper and hence to prevent printing troubles from taking place due to the condensation on the print head.